Field of the Invention
The present invention relates to a light source control device and a light source control method in a case where a plurality of light sources, such as light emitting diodes (hereinafter referred to as “LEDs”) or lasers, are used.
Description of the Background Art
In recent times, as light sources of projection video display devices, an aggregation of a plurality of LEDs connected in parallel have been developed to be used. The advantage of the parallel-connected LEDs is that the large number of LEDs can be driven at low voltage and that light sources in high luminance can be obtained by lighting the plurality of LEDs. Thus, in comparison to devices including conventional lamp light sources, the devices including the light sources formed of the plurality of LEDs connected in parallel can suppress power consumption of the whole devices.
The LEDs have been known that vary in luminance according to a drive current supplied, and a user sets the drive current through a control device such as a microcomputer to obtain desired luminance. A method for setting the drive current from the control device such as the microcomputer to adjust the luminance of the LED light sources is, for example, technologies disclosed in Japanese Patent Application Laid-Open No. 2007-95391 and Japanese Patent Application Laid-Open No. 2007-96113.
The plurality of LED light sources connected in parallel have the advantage that a video display can continue because even if an open fault causes an unlit LED, the other normal LEDs in which no fault occurs light up. However, a fault cannot be detected because when the light goes out due to an open fault, the other normal LEDs in which no fault occurs continue to light up. A rated current or more may flow through the other normal LEDs according to an amount of a drive current being set. This may cause a further fault, and faults may occur in all of the LEDs.